Alternating piston pump or prime mover



Dec. 20, 1949 J. DOMMISSE ET AL ALTERNATING PISTON PUMP 0R PRIME MOVERFiled March 22, 1946 INVENT RS Jan Dommnssc and EH: ROdQFICK MGJL'HQSonThen HCt00'h? 1 Patented Dec. 20, 1949 ALTERNATING PISTON PUMP OR PRIMEMOVER Jan Dommisse and Eric Roderick Matheson, Johannesburg, Transvaal,Union of South Africa Application March 22, 1946, Serial No. 656,290

8 Claims. (01. 103-129) This invention relates to a rotary device orengine which is suitable for use as a pump or prime mover.

One object of this invention is to provide such device which combinesthe advantage of positive action of the same kind as is obtained withreciprocating engines, with the advantages arising from the use ofpurely rotary movement.

Another object is to provide a rotary device or engine of simple andsturdy construction.

A further object of this invention is to provide a rotary device orengine which can be easily and quickly assembled and dismantled.

A further object of this invention is to provide such device or enginewhich can operate over long periods without appreciable diminution ofcapacity due to wear, and in which those rotary parts which are mainlyexposed to wear can be easily replaced.

A further object of this invention is to provide a pump of simple andsturdy construction and high efficiency, which needs little or nosupervision and is thus particularly suitable for use as a borehole ordeep well pump.

In one aspect of this invention, a rotary device suitable for use as apump or prime mover, comprises two co-axial cylinders, at least twopistons arranged for rotation in the annular space between saidcylinders and about the axis of said cylinders, and shaped to divide theannular space between said cylinders into compartments; and means for sorotating said pistons as to vary, during each complete revolution, thespace of each such compartment from a maximum to. a minimum and: backagain to a maximum. When "this device is to be used as a pump, means areprovided for introducing fluid into each of said chambers when thevolume of said chamber is being increased to its maximum, and forreleasing fluid therefrom while the volume of the respectiv chamber isbeing decreased to its minimum. J-

In one form of this invention a device suitable for use as a .pump orprime'mover comprises a cylinder, a plurality of. pistons within saidcylinder and constrained forimovement along a' path which is co-axialwith, said cylinder, adriving member the axis of which is parallel withthe axis of said cylinder and offset from said cylinder axis, andmovable linksconnecting each of said pistons to said driving memberwhereby continuousrotation of said driving member at constant angularspeedbrings aboutrotation of said pistons combined witharelativemovement of said pistons towardsand away from one another. 65

In this specification and the claims attached thereto the term piston isintended to include vanes, blades, and other equivalent means.

In a preferred form, a device according to this invention comprises amaterially tubular casing providing an inlet and an outlet; a cylinderwithin said casing, said cylinder being closed at its one end by a platewhich is formed with a hole that provides the sole communication betweenthe inside of the cylinder and said casing inlet; a bearing, at theother end of the cylinder, for a driving means, said bearing beingeccentric with respect to said cylinder; driving means seated in saidbearing and adapted to be connected to a driving shaft; an innercylinder within and co-axial with the first said cylinder; at least twopistons which divide the annular space between said two fcylinders intocompartments and which are arranged for orbital movement about saidinner cylinder; connecting means between each of said pistons and saiddriving means; and an outlet port in the wall of the first said cylinderconnected to said casing outlet. Preferably the casing is integral withsaid cylinder, the axis of said casing being parallel to the axis ofsaid cylinder but ofiset from said cylinder axis, said casin extendingat both its ends beyond the open ends of said cylinder and being formedwith recesses which are co-axial with said casing and which provideseats for said plate, at the one end of said cylinder, and for saidhearing at the other endof said cylinder; said bearin and said platebeing held on said seats by screw-caps which are screwed into the endsof said casing and which provide respectively the inlet means and theoutlet means-of said casing.

The driving means may comprise two members which are constrained forrotation with one another but which have axially a limited freedom ofmovement with respect to one another; one of'said members being adaptedto 'be connected to a driving shaft whilst the other member has attachedthereto the aforesaid connecting means.

Said connecting imeans preferably comprises a pin on the piston which isparallel with the axis of said cylinders, a pin extending from thedriving means and parallel with the first said pin, and a link pivotallyconnected to each of said pins.

The pistons are formed to make close contact with the inside of the onecylinder as well as with the outside of the inner cylinder, whilst beingfreely rotatablefabout said inner cylinder. For ,this, purpose, eachpiston preferably com.

prises an outer member formed with an arcuate surface of the samediameter as that of the inside of said first cylinder, an inner memberformed with an arcuate surface of the same diameter as that of theoutside of said inner cylinder, the two arcuate surfaces beingconcentric with one another, a radial member connecting said outermember to said inner member, and resilient sealing means extending inthe axial direction along materially the whole length of the innerarcuate surfaces and secured in recesses provided in said surfaces.Preferably, one or more grooves may be provided extending in the axialdirection along materially the whole length of the outer arcuatesurfaces.

Pistons of the kind specified in the last preceding paragraph arecomprised in and form part of this invention.

An example of this invention is illustrated in the accompanyingdrawings, in which:

Fig. 1 is a sectional elevation of a deep-well pump on line 1-1 of Fig.2.

Fig. 2 is a section, on line II--II of Fig. 1.

Fig. 3 is a plan of the pump with its upper cap removed and partlysectioned on line IIIIII of Fig. 1.

With reference to the figures, I indicates the tubular pump casing whichhas a cylinder 2 formed integral therewith. The casing is of generallycylindrical form and has its axis (see Fig. 2) parallel with, but offsetfrom the axis 0 of said cylinder 2. The casing I is threaded at 3 toreceive an inlet cap 4 which latter is threaded at 5 for connection witha suction pipe or a strainer, or with a footvalve and strainer or thelike. The casing I is further threaded at 6 to receive an outlet cap 'Iwhich has its outlet end 8 threaded at 9 for connection with the risingmain conveying the water delivered by the pump to the surface.

The cylinder 2 is closed at its inlet end by a plate II) the spigotedend I I of which fits into said inlet end and which provides the inletport I2; and is closed at its other end by a bearing IS the spigoted endI4 of which fits into said other end of the cylinder 2. At its side thecylinder 2 is formed with an outlet port I5 which is connected by portsI6 and IT with the pump outlet 8.

The plate It and the bearing I3 are seated in recesses I8 and I9 in thecasing which are concentric with the casing but eccentric with respectto said cylinder 2; and are securely held in position by said inlet cap4 and outlet cap 1 respectively. 20, 2|, 22 and 23 are packing ringsarranged to provide fluid tight joints at the ends of the casing I andcylinder 2.

Housed in the bearing I3 are the driving member 24 and the transmittingmember 25 which are constrained to rotate together as by pins 26 whichlatter are fixed into bosses 21 of member 24 on the one hand, andslidably project into suitably shaped recesses 28 in the flanged part 29of the second member 25 on the other hand; and which leave the members24 and 25 free for axial movement relatively to one another...

The transmitting member 25 is adapted to be connected to a driving shaft36,. and has for this purpose its end 3|, which projects out of thebearing, recessed and screw-threaded at 32 to receivethe screw-threadedend 33 of said shaft. The driving shaft is secured to the member 25 asby a lock-nut 34; and a shield 35 is arranged on said projecting end 3Iofv member 25 andis secured thereto as by said lock-nut 34. 'Said shield35 loosely encloses the boss 36 of the beariii) ing I3.

ing I3 and prevents entry into the bearing-of sediment, such as maysettle out from the water column in the rising main while the pump is atrest.

The transmitting member 25 is free to move axially between a position inwhich the upper face at of its flanged portion 29 bears against thesurface 38 of the bearing I3, and a second position, in which the shield35 bears against the boss 36 of the bearing I3. The respective parts areso dimensioned that the transmitting member 25 has sufficient freedom ofaxial movement to compensate for expansion and contraction in the driveshafting and thus relieves driving member 24 from strain caused byexpansion or contraction in said shafting.

The driving member 24 has is lower face resting on the pistons 39, 40,4| flush with the spigotted-face I 4 of the bearing I3 and has its upperface located by the inner surface 38 of the bear- Said driving member isprovided with three equally spaced bosses 42 in each of which is secureda driving pin 43 which extends into the cylinder 2 and is connectedtoone of said pistons.

Located in the cylinder 2 is the inner cylindrical member 44 whichreaches from the plate ID to the driving member 24 and is fitted withrenewable top and bottom caps 45 and 46. Said inner cylindrical member44 is free for relative rota, -tional movement with respect to saidcylinder 2, plate I6, and driving member 24, and is held substantiallyco-axial with said cylinder 2 by said pistons but is at the same timefree to move radially to the extent of the clearances between thecylindrical member 44 and the pistons and between the pistons and thecylinder 2 Whilst, in turn, restraining said pistons for orbitalmovement along a path which is concentric with said cylinder 2.

The pistons 39, 46 and M are spaced about the inner cylindrical member44 and are arranged for relative sliding movement with respect tocylinder 2, inner cylindrical member 44, plate ill and bearing I3. Theclearances between the pistons and said plate In and bearing I3 are madesmall in order to reduce slippage of fluid past the pistons. For thesame purpose, the outer faces 41 of the pistons are made incross-section of arcuate shape of the same diameter as that of the innerwall 48 of the cylinder .2, and are provided with grooves 49 extending,in the axial direction, along the whole height of the pistons. Inoperation, centrifugal force in conjunction with the forces transmittedby the links 58 tends to maintain the outer faces of the pistons inclose contact with the cylinder wall 48 and thus reduces slippagebetween them. Similarly, the inner face 50- of each piston is formedsuitably to reduce slippage between itself and the, inner cylindricalmember 44. In the example, each such face is, in cross-section, ofarcuate shape of the same diameter as that of the outside of said innercylindrical member 44. Further, by virtue 'of the freely movable cylin.drical member 44, fluid pressure in the chambers subject to the outletpressure of the pump causes the cylindrical member 44 to bear againstthe pistons enclosing the chambers subject to the inlet pressure of thepump, said pistons in turn bearing against the cylinder 2-; thus, aneffective seal is maintained between the chambers under high fluidpressure and the chambers under low fluid pressure which will compensatefor such radial wear as may result from'normal operation.

'In' addition; each "inner piston face is formed with a groove in whichis secured a packing strip In the example, each piston comprises anouter portion 52 which provides the outer face 41, an inner portion 53which is peripherally substantially shorter than said outer portion 52and which provides theinner face 50, and an intermediate portion 54which connects said two portions 52 and 53 to one another. Said threeportions 52, 53 and 54 will be in most cases integral with one another,and are so illustrated in the drawings.

Each piston is further provided with two bosses 55, 55 in which issecured a piston pin 56 which is held immovable with respect to thepiston as by a grub screw (not shown) which engages a recess 51 in thepin. A Each piston pin is connected to its corresponding driving pin bya link 58 which is arranged for pivotal movement with respect to bothits piston pin and itsdriving pin.

In use, the pump assembly is suspended in the borehole from the risingmain which is screwed into the top cap 1. The motive power is pro-,vided on thesurface of the borehole by a suitable prime mover and istransmitted by drive shafting, preferably located inside the risingmain, to the driving shaft of the pump assembly. The rotary movement ofthe driving shaft 30 is transmitted by the transmission member 25 to thedriving member 24. Rotation of said driving member 24 causes the drivingpins 43 to move in a circular path about the casing axis 0. The rotarymovement of the driving pins is transmitted through the links 58 to thepistons 39,

40 and-4i and causes the latter to rotate in their orbital path aboutthe cylinder axis 0 As a result of the eccentricity of the path'of thedrivin pins with respect to the orbit of the pistons, rotary movement ofsaid driving pins at constant angular velocity causes the pistons toaccelerate during one part of each orbital movement and to decelerateduring another part of said movement, each piston being acceleratedrelative to the next preceding piston during one part of the orbitalmovement and decelerated relative thereto during another part of saidmovement.

When the leading piston is being accelerated relative to the trailingpiston the chamber defined between the oo-acting surfaces of the twopistons expands and increases its volume. When, on the other hand, theleading piston is being decelerated relative to the trailing piston, thedistance between the co-acting surfaces of the two pistons e decreases,and the chamber defined between said surfaces contracts and decreases involume accordingly.

Durin each complete orbital movement of the pistons each of the threechambers 59, 60, 6| decreases from a maximum to a minimum and increasesagain to said maximum.

In Figure 2, the chamber BI is shown to be at a minimum, whilst thechamber 60 is about to increase to its maximum.

The arrangement is such that each chamber is in communication with theinlet port 12 during that part of the cycle during which said chamber isincreasing to its maximum, and that said chamber opens to the outletport during that part of the cycle during which the volume of thechamber is being decreased to a minimum. In the example, the trailingpiston closes the suction port 12 when the chamber volume approaches amaximum, and immediately afterwards the lead- 6 ing piston uncovers theoutlet port 15. The chamher is now in direct communication with thecasing outlet 8, through the outlet port 15, andthe apertures I6 and I1.While the chamber. is so connected to the casing outlet, the volume ofthe chamber is decreased from a maximum to a minimum, and acorresponding portion of the water, previously sucked into the chamberfrom inlet port I2, is forced out of the chamber by the contractingmovement of the latter. When the chamber volume approaches a minimum,the trailing piston covers the outlet port I5 whilst immediatelyafterwards, the leading piston uncovers the suction port l2, whereuponthe cycle of operation begins anew.

We claim:

1. A rotary piston machine suitable for use as'a pump or prime mover,comprising a materially tubular casing providing an inlet and an outlet;2. cylinder within said. casing, said cylinder being closed at its oneend by a plate which is formed with a hole that provides the sole com:munication between the inside of the cylinder and said casing inlet; abearing, at the other end of the'cylinder, for a driving means, saidbearing being eccentric with respect to said cylinder; driving meansseated in said bearing and adapted to be connected to a driving shaft; afreely floating cylindrical member within said cylinder; at least twopistons which are arranged to hold said cylindrical member materiallyco-axially with said cylinder and which divide the annular space betweensaid cylinder and said cylindrical member into compartments and whichare, in turn, constrained by said cylindrical member for a movementco-axial with said cylinder; con necting means between each of saidpistons and said driving means; and an outlet port in the wall of saidcylinder connected to said casing outlet.

2. The machine claimed in claim 1, in which the driving means comprisesa first member which is adapted to be connected to a driving shaft and asecond member to which said connecting means are attached; said firstmember having a limited amount of freedom of axial movement relativelyto said second member but being constrained for rotary movement co-axlalwith said second member.

3. The machine claimed in claim 1, in which the casing is integral withsaid cylinder, the axis of said casing being parallel to the axis ofsaid cylinder but offset from said cylinder axis, said casing extendingat both its ends beyond the open ends of said cylinder and being formedwith recesses which are co-axial with said casing and which provideseats for said plate, at the one end of said cylinder, and for saidbearing at the other end of said cylinder.

4. The machine claimed in claim 1, in which the casing is integral withsaid cylinder, the axis of said casing being parallel to the axis ofsaid cylinder but offset from said cylinder axis, said casing extendingat both its ends beyond the open ends of said cylinder and being formedwith're cesses which are co-axial with said casing and which provideseats for said plate, at the one end of said cylinder, and for saidbearing at the other end of said cylinder; said bearing and said platebeing held on said seats by screw-caps which are screwed into the endsof said casing and which provide respectively the outlet means and theinlet means of said casing.

5. The pump claimed in claim 1 in which the driving means comprises afirst member which is connected to a driving shaft and a second memberto which means are attached which connect said second member to the pumppistons; said first member being axially movable with respect to saidsecond member, but being constrained for rotary movement co-axial withsaid second member; and a shield which is interposed between said firstmember and said driving shaft; said shield being arranged to protect thebearing of said first member against sediment and to limitunidirectionally the freedom of axial movement of said first member,relatively to said second member.

6. A pump comprising a cylinder; a cylindrical member within saidcylinder and suitable to be held materially co-axially with saidcylinder, said cylindrical member being freely movable radially withrespect to said cylinder; at least two pistons arranged for rotation inthe annular space between said cylinder and said cylindrical member,said pistons being formed suitably to hold said cylindrical membermaterially co-axialiy with said cylinder and being shaped to divide saidannular space into compartments; a plurality of resilient sealing meansin the face of each piston adjoining said cylinder, each such meansextending in the axial direction along materially the whole length ofthe piston; and means for so rotating the pistons as to vary, duringeach complete revolution, the space of each compartment from a maximumto a minimum and back again to a maximum.

7. A rotary piston pump, comprising a materially tubular casingproviding an inlet and an outlet, said inlet and said outlet beingarranged at opposite ends of said casing and being materially co-axialwith the latter; a cylinder within said casing, said cylinder beingclosed at its one end by a plate which is formed with a hole thatprovides the sole communication between the inside of the cylinder andsaid casing inlet; a bearing at the other end of the cylinder for adriving means, said bearing being eccentric with respect to saidcylinder; at least two rotary pistons within said cylinder; drivingmeans seated in said bearing and arranged to accelerate each pistonpositively during one part of each complete orbital movement of suchpiston and to accelcrate said piston negatively during another part ofsaid movement, said driving means comprising a first member which isconnected to a driving shaft and a second member to which means areattached which connect said second member to the pistons, said firstmember being axially movable with respect to said second member butbeing constrained for rotary movement co-axial with said second member,and a shield interposed between said first member and said drivingshaft, said shield being arranged to protect the bearing of said firstmember against sediment and to limit unidirectionally the freedom ofaxial movement of said first member relative to said second member, apassage extending between said casing and the outside wall of saidcylinder and materially parallel with the latter; and an outlet port inthe wall of said cylinder, said outletport being connected to saidcasing outlet by said passage.

8. A rotary piston pump, according to claim 7, in which the first memberof the driving means is axially movable with respect to thesecond'member but constrained for rotary movement coaxial with suchsecond member by pins which are secured to one of said members and whichproject into recesses in the other member.

JAN DOMMISSE. ERIC RODERICK MATHESON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 664,938 Fong Jan. 1, 1901 665,390Brown Jan. 1, 1901 727,171 Mayer May 5, 1903 2,095,987 Kratzer Oct. 19,1937 2,394,337 Sobek Feb. 5, 1946 FOREIGN PATENTS Number Country Date1,732 Great Britain Apr. 21, 1881 159,250 Great Britain Feb. 22, 192127,126 France Jan. 9, 1924 358,081 Great Britain g Oct. 28, 1931

